If you're using Facebook, you're almost certainly familiar with Pages.These are the Facebook pages on which you click Like, rather than sending a friend request. Typically they're used for businesses of all types. Public figures use them as well. A lot of people prioritize the number of fans over everything else. Two of the common ways to quickly build the number of fans are to buy them or to run a promotion.
I'd avoid the first one entirely. Tread lightly with the second one.
If you do an Internet search for "buy Facebook fans," you'll see a number of services out there that offer to build your fan numbers for a fee. They do what they say they will — if you sign up, you'll see a jump in the numbers very quickly. (This is different from a Facebook ad; ads target real people who are in your real target market, and that's a topic for another post.)
However... these numbers don't actually mean a lot to you, and they screw up your data. Facebook provides a tool called Insights, which shows you all sorts of information about your audience. But if a lot of these Likes are coming from purchased fans, the Insights page isn't telling you much anymore. You can post incredible content that's so beautifully written it makes you weep with joy, but it will look like it's getting a tepid response because the purchased fans are not people who look at your page.
Now, promotions. Contests, sweepstakes, giveaways, etc. If you're going to run one, the first thing you must do is check Facebook's rules on how to do them. Do it incorrectly, and they can take your page down, which is devastating for a small business that needs Facebook to survive. (Again, a topic for a whole post of its own.)
Once you're positive you're OK with the rules, make sure that the promotion you're running is what your people want, not just what boosts your numbers. The opportunity to win a trip to the Super Bowl is a great prize for the right audience. But if you're in the business of selling ukuleles, run a contest for that and you're going to end up with a lot of people on your page who don't play the ukulele and aren't interested in learning, and you're going to spend a lot of time cleaning up their comments.